SES light after routine service

[Shire Ben]

Hello,

Background 2004.5 LLY with approximately 80K miles, no mods, oil changes every 4K, transmission and filter every 25K and fuel filter at 12k. Truck was serviced at local diesel service center today LOF and FF (Napa 3910). As soon as truck was started after service SES light came on...U106, tech was able to clear code, but immediately came back on. Called local chevy dealer who stated it was trouble with glow plug controller communication system. Checked all connections, Air filter was checked, ?? air intake heater issue. All glow plugs functioning and truck appears to function normally except glow plug light stays on in cold weather until engine starts and then goes out. SES light remains on...Truck has had no issues for three years. Driven 500-600 miles/week, minimal towing. Local diesel shop is very good...no concerns. Took it to local Chevy dealer, but have to wait until "diesel tech" is in on Monday. Any additional thoughts would be appreciated. Thanks you, Andy

[Shire Ben]

This AM is was 8 degrees with 15-20 mile wind making it below zero. Truck barely started with glow plug light remaining on until truck started. Once running it is fine, just with SES light. I will keep truck plugged in at night until this is resolved. Please offer any other suggestions. Thanks, Andy

[DieselMonk]

If you have a DC current clamp you could find the wires that go to that intake heater and measure if it works or not. Maybe it is a simple fuse or something... you also could probably use an Ohm meter, unplug the intake heater and measure the resitance there. I don't know what a good value would be, so someone else has to chime in. Other than that you have to wait for Monday for the diesel tech to come in ;)

DM

[Shire Ben]

Thanks Dieselmonk,

Checked main Glowplug circuit and that has power. I am not sure where air intake heater circuit or element is located. I looked from airfilter to top of engine. Thanks, Andy

[Putzboy]

Intake air heater should be right where the intake tube (plastic) attaches to the intake (metal). There's a single wire that attaches to the top, much like the glow plugs.

I looked in my service manual for my '02, but a U106 code does not exist for my year.

Common glow plug circuit problems show up as a P0380. I know, I am experiencing those problems right now. I suspect the relay, since I have replaced all the plugs and the intake heater at this point. LOL

8 degrees huh? Too cold for me, when it was in the 20's here last week, I just about froze my hind end off!

[DmaxMaverick]

This AM is was 8 degrees with 15-20 mile wind making it below zero. Truck barely started with glow plug light remaining on until truck started. Once running it is fine, just with SES light. I will keep truck plugged in at night until this is resolved. Please offer any other suggestions. Thanks, Andy

The U106 code is incomplete. It should be a letter, followed by 4 numbers. The U10xx series of codes is a diagnostic port communication error, but not a specific fault code. Could be low voltage, ground, or a connector issue. Failing batteries or poor terminal connections are usually the cause. Even though there seems to be enough battery to start and run, these things are very sensitive to even one failed cell in a battery. If your batteries are OEM still, definately consider them suspect.

For the sake of argument when figuring tempurature into trends, don't include the wind chill. The actual temp (8

[Shire Ben]

D-max and Putzboy,

Thanks for your response. I will definitely pass on your suggestions to my local Chevy dealer. I would have stayed with my local diesel mechanic who is very trust worthy, but since engine is still under warranty I will have dealer take care of it. In regards to DTC, my guess is that diesel shop does not have as sophisticated equipment as dealer does, but clearly more experience dealing with diesels. D-max, appreciate the wind chill information...you are correct. What are your thoughts on the wind during these low temperatures and hold it cold soaks the vehicle. Clearly, this must impact the vehicle temperature and starting. My company operates three twin engine turbine helicopters and this makes a big difference especially on first start of day if not in hangar. Any additional thoughts about driving the truck with DTC on...does not appear any different, but MPH may have gone down, but may be due to cold weather. One other questions...truck is only three years old. Would batteries go this soon and can they check cells on sealed batteries?? Thanks, Andy

[JohnC]

Wind chill affects how quickly the vehicle cools down, but not the ultimate temperature it reaches. After enough time has passed, a vehicle at 8* in 100 mph winds will start exactly like one in 8* and calm winds. You on the other hand will not...